You can't drink you favorite drink while it is boiling (ouch!), so you let it sit and cool for a few minutes. It was boiling when you first poured it and it cooled to 75oC when you finally drank it. How much heat was LOST from your water?

To calculate the heat lost from the water, we can use the **formula for heat transfer**:

\[
Q = mc\Delta T
\]

where:  
- \(Q\) = heat lost (in joules, J)  
- \(m\) = mass of water (in kilograms, kg)  
- \(c\) = specific heat capacity of water, which is \(4,186 \, \text{J/kg} \cdot \text{°C}\)  
- \(\Delta T\) = change in temperature (in °C)

---

### Step 1: Identify what we know  
- Assume \(m = 1 \, \text{kg}\) (this corresponds to 1 liter of water).  
- The boiling temperature of water is \(100^\circ \text{C}\).  
- The final temperature when it was ready to drink was \(75^\circ \text{C}\).  

\[
\Delta T = 100^\circ \text{C} - 75^\circ \text{C} = 25^\circ \text{C}
\]

---

### Step 2: Calculate the heat lost  

\[
Q = (1 \, \text{kg})(4,186 \, \text{J/kg} \cdot \text{°C})(25^\circ \text{C})
\]

\[
Q = 104,650 \, \text{J}
\]

So, the amount of **heat lost from the water** is **104,650 joules** (or about **104.65 kJ**).

---

Do you have any questions or want more details on any part of this calculation? 

Here are five related questions:
1. What if the water mass was 500 grams instead of 1 kg?
2. How would the result change if the drink cooled to 60°C instead of 75°C?
3. What is the significance of the specific heat capacity of water being high?
4. How much time would it take for the drink to cool under certain conditions (Newton’s Law of Cooling)?
5. What are the units of heat, and how do joules relate to calories?

**Tip:** A **joule** is the SI unit of energy, and you can convert joules to calories by dividing by 4.184.

You can't drink your favorite drink while it is boiling (ouch!), so you let it sit and cool for a few minutes. It was boiling when you first poured it and it cooled to 75°C when you finally drank it. How much heat was LOST from your water?

Discover how to calculate the heat lost when water cools from boiling (100°C) to 75°C. This step-by-step solution uses the heat transfer formula (Q = mcΔT) and covers key thermodynamics concepts. Ideal for students in Grades 9-12 studying heat transfer.

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